Comparative Analysis of a Critical Brain Structure: The Basal Ganglia

新大脑皮层一直是致力于确定人脑独特特征的进化研究的理论和实验焦点；然而，新大脑皮层只是人类智力基础神经网络的一个元素。它直接连接并依赖于其他皮质下结构，特别是基底节。传统上，人们知道基底神经节调节运动功能。然而，最近，它们被发现活跃在高级认知中，它们对前额叶皮质活动的调节表明，它们在语言、学习和记忆等过程中与新皮质一样重要。本研究的目的是通过比较各种灵长类动物的代谢和调节成分，研究基底节在人类认知发展中的作用，包括人类和我们最接近的近亲黑猩猩。这些方法将结合先进的体视学和免疫组织化学，以量化神经元与胶质细胞的比率，神经调节神经元，以及关键基底节区域内的神经调节轴突。这项研究将提供关于这些皮质下结构的新知识，包括人类进化过程中可能发生的任何重组。这将有助于将我们的基底节与其他灵长类动物区分开来，促进对它们在灵长类进化过程中如何变化的理解，以及系统发育差异可能如何与认知过程有关。这项研究还可能通过识别人类在受这些疾病影响最严重的基底节区域与其他物种的不同，为理解主要神经病理疾病(如亨廷顿病和帕金森病)的病因学做出重大贡献。许多灵长类物种的组织切片和幻灯片将被生成、存档，并提供给其他研究人员进行额外的比较研究。这项工作还将为研究生和本科生提供培训，包括那些注册参加麦克奈尔学者计划的学生，该计划为来自代表性不足群体的个人准备博士学习。

The neocortex has been both the theoretical and the experimental focal point of evolutionary studies dedicated to identifying unique features of the human brain; however, the neocortex is only one element of a neural network underlying human intellectual abilities. It is directly connected to and dependent upon other subcortical structures, especially the basal ganglia. Traditionally, the basal ganglia were known to regulate motor functions. Recently, however, they have been revealed to be active in advanced cognition, and their regulation of prefrontal cortical activity demonstrates that they are as important as the neocortex in processes such as language, learning, and memory. The goal of the present research is to examine the role of the basal ganglia in human cognitive development by comparing metabolic and modulatory components across a wide range of primate species, including humans and our closest living relative, the chimpanzee. The methods will combine advanced stereology with immunohistochemistry in order to quantify neuron to glia ratios, neuromodulatory neurons, and neuromodulator axons within key basal ganglia areas. This study will provide new knowledge about these subcortical structures, including any reorganization that may have occurred during human evolution. This will help distinguish our basal ganglia from those of other primates, promote understanding of how they changed during primate evolution, and how phylogenetic differences may relate to cognitive processing. The research also may contribute substantially to understanding the etiology of major neuropathologies, such as Huntington's and Parkinson's diseases, by identifying how humans differ from other species in the basal ganglia regions most affected by these diseases. Histological sections and slides of many primate species will be generated, archived, and made available to other researchers for additional comparative studies. This work also will provide training for graduate and undergraduate students, including those enrolled in the McNair Scholars Program, which prepares individuals from under-represented groups for doctoral study.